1. Filed the Invention
The present invention relates to packaging structures of an energy storage device, more particularly to at least one unit cell of capacitor by being repeatedly stacked and packaged to form the energy storage device.
2. Description of Related Art
A traditional capacitor comprises a pair of metallic collectors, a pair of electrodes, electrolyte, and a separator. The outer layer of the electrode is the metallic collector. The separator which is porous and the electrolyte are interposed between the two electrodes. In that the electrolyte is in the form of liquid or gel, a separator is needed to be interposed between the electrodes to prevent self-discharge and short circuit. The leakage of the electrolyte also needs to be prevented by polymeric sealing rings outside the pair of collectors. The packaging process can be completed by following steps of two leads penetrating a plastic case which may be made of polyvinylchloride (PVC) from outside, the two leads being welded on the surfaces of the metallic collectors, epoxy being injected into the case and then cured. In that there are many concerns of the traditional capacitor, such as leakage of the electrolyte and current steering on the collector, the packaging process of the traditional capacitor is far more complicated; moreover, there are more problems of being toxic, easily combustible, leakage, not being safe for use, and higher manufacturing cost.
To boost output voltage and power, traditional capacitors are connected both in series and in parallel and are manufactured by drilling, welding, screwing with nails and different ways of wire connection to become a capacitor module with high performance. Consequently, the manufacturing process becomes more complicated and the cost for that is also raised and the volume of the capacitor module becomes bigger. A traditional capacitor possesses only single unit cell. This is due to the high electrical resistance of the electrodes of the unit cell, which make it not appropriate to fabricate a traditional capacitor by packaging stacked unit cells in series to boost the voltage and power.